1. Field of the Invention
The present invention relates to a process for separation of bastnaesite and other rare earth minerals from complex, weathered ores containing barite, fluorite, bastnaesite, monazite or other rare earth minerals using a flotation process. The flotation process involves reverse stage flotation of barite, followed by flotation of fluorite and at the end, bastnaesite. Each flotation stage involves the use of innovative, modification and flotation agents.
2. Description of Prior Art
In the art, a limited number of processes are known for treatment of various ores containing bastnaesite, mainly from unaltered ores. One such process is presented in the U.S. Pat. No. 4,772,382 (September 1988), where a novel collector emulsion is used to recover bastnaesite by flotation from an ore that contains silicates and feldspar. In this case, the slurry of ground material is stage-conditioned with modifying agent and a novel collector emulsion, followed by bastnaesite flotation.
In a published paper, ‘An alternative reagent scheme for the flotation of Mountain Pass rare earth ore’ in the Proceedings of the XIV International Mineral Processing Congress (Oct. 17-23, 1982—Toronto, Canada), a commercial process was described involving flotation of bastnaesite from the associated gangue minerals of calcite (40%) barite (25%) and silica (8%), using a tall oil fatty acid as a collecting agent, and lignin sulponate+sodium fluorosilicate as a gangue depressing agent at elevated temperature. In order to enhance selectivity, the ore-water slurry is heated to a temperature of 90° C. Furthermore, the Japanese patent 55-119456(3) describes a process for froth flotation of bastnaesite from complex barite, fluorite, and rare earth ores containing bastnaesite as a rare earth mineral. According to this invention, the pulp slurry is conditioned with a sulphonate collecting agent and barite/fluorite are recovered by froth flotation ahead of bastnaesite. The resulting barite/fluorite flotation tailing is reconditioned at an elevated temperature and bastnaesite is separated by flotation from the other gangue minerals.
There are a number of references [3, 4, 5, 6, 7] to processes involving the separate flotation of barite and fluorite from barite/fluorite, barite or fluorite ores, to recover barite and fluorite in separate, marketable products. Neither the barite nor the fluorite flotation processes can be successfully applied in the beneficiation of bastnaesite ores containing barite and fluorite, especially if the ore is altered.
It has been demonstrated that separation of bastnaesite from barite and fluorite altered oxidized ore, using conventional flotation techniques, is not possible.